title: Atomic and electronic structures of amorphous Ge(2)Sb(2)Te(5); melt-quenched versus ideal glasses.
abstract: To investigate an amorphous structure of Ge(2)Sb(2)Te(5) that satisfies the 8-N rule (so-called 'ideal glass'), we perform alternative melt-quench simulations on Si(2)As(2)Se(5) and replace atoms in the final structure with Ge-Sb-Te. The resulting structures have salient features of the 8-N rule such as the tetrahedral configuration for all Ge atoms and the localized Te lone pairs at the valence top. In addition, the average Ge-Te and Sb-Te distances are in good agreement with experiment. The energetic stability of the ideal glass supports the existence of this amorphous structure that is distinct from the melt-quenched glass. From the analysis of electronic structures and optical dielectric constants, it is concluded that the electronic character of the melt-quenched amorphous Ge(2)Sb(2)Te(5) lies in between the resonant p-bonding of the crystalline phase and the covalent bonding of the ideal glass.
authors.affiliation: Department of Materials Science and Engineering, Seoul National University, Seoul 151-744, Korea.
authors.forename: E
authors.initials: E
authors.lastname: Cho
authors.forename: J
authors.initials: J
authors.lastname: Im
authors.forename: C
authors.initials: C
authors.lastname: Park
authors.forename: W J
authors.initials: WJ
authors.lastname: Son
authors.forename: D H
authors.initials: DH
authors.lastname: Kim
authors.forename: H
authors.initials: H
authors.lastname: Horii
authors.forename: J
authors.initials: J
authors.lastname: Ihm
authors.forename: S
authors.initials: S
authors.lastname: Han